Your commit:
cifs: set ra_pages in backing_dev_info
Commit 522440ed made cifs set backing_dev_info on the mapping attached
to new inodes. This change caused a fairly significant read performance
regression, as cifs started doing page-sized reads exclusively.
By virtue of the fact that they're allocated as part of cifs_sb_info by
kzalloc, the ra_pages on cifs BDIs get set to 0, which prevents any
readahead. This forces the normal read codepaths to use readpage instead
of readpages causing a four-fold increase in the number of read calls
with the default rsize.
Fix it by setting ra_pages in the BDI to the same value as that in the
default_backing_dev_info.
Fixes https://bugzilla.kernel.org/show_bug.cgi?id=31662
Cc: [email protected]
Reported-and-Tested-by: Till <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
has been added to the upstream SCSI tree
You can find it here:
http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commit;h=2b6c26a0a62cc0bab0ad487533d5581d7c293fef
This patch is scheduled to be pushed when the merge window opens for 2.6.39
James Bottomley
P.S. If you find this email unwanted, set up a procmail rule junking on
the header:
X-Git-Tree: SCSI
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